Raptor Computing Systems Hardware > Talos II

OpenBMC password

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MPC7500:
Here it's written
https://wiki.raptorcs.com/wiki/Talos_II_Beginner%27s_Quick_Start_Guide#Changing_The_Password

atomicdog:
That's for changing a password when you're already able to login, but I meant for recovering access and resetting a lost password.

Borley:
As far as I know, a lost or forgotten BMC password basically requires reflashing the BMC chip. But if you're already logged into the BMC, changing it should be as simple as running
--- Code: ---passwd
--- End code ---
and very carefully entering the new passphrase, three times. I have discovered (through my own painful experience :P) that the separate password for the boot menu (Petitboot) can more easily be reset.

bobpaul:

--- Quote from: atomicdog on March 14, 2022, 09:50:35 pm ---I'm still curious on how logging into the serial console is suppose to allow you to reset the password though. I don't see any OpenBMC documentation about it. I found this: https://docs.graphcore.ai/projects/bmc-user-guide/en/latest/serial-rescue.html ...but is it specific to graphcore processors or generic to OpenBMC?

--- End quote ---

I tried the instructions at graphcore.ai with no luck. But the instructions on the wiki for Resetting the BMC's Persistant Storage worked for me on two systems. After wiping the persistent storage, I was able to log into the BMC with the default password and get all the firmwares updated.

draconx:

--- Quote from: bobpaul on February 07, 2024, 10:09:18 pm ---I tried the instructions at graphcore.ai with no luck. But the instructions on the wiki for Resetting the BMC's Persistant Storage worked for me on two systems. After wiping the persistent storage, I was able to log into the BMC with the default password and get all the firmwares updated.

--- End quote ---

Wiping the entire persistent storage seems like total overkill if the only problem is that you forgot the BMC root password.

All you need to do is edit the shadow file on the overlay filesystem with a new password.

Follow that wiki page instructions to add overlay-filesystem-in-ram to the boot command line via u-boot.  This enables a root console login with the default root password of 0penBmc.  Once logged in, mount the writable overlay partition somewhere, for example:


--- Code: ---# mount -t jffs2 /dev/mtdblock5 /mnt
--- End code ---

Then the simplest way is probably to just copy /mnt/cow/etc/shadow over /etc/shadow, run passwd, then copy the newly-updated /etc/shadow back to the writable partition, for example:


--- Code: ---# cp /mnt/cow/etc/shadow /etc/shadow
# passwd
New password:
Retype new password:
Retype new password:
passwd: Password updated successfully
# cp /etc/shadow /mnt/cow/etc/shadow
--- End code ---

Or just run an editor on /mnt/cow/etc/shadow and manually change the root password hash to whatever you want.  Then reboot, and voila, shiny new BMC root password.

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